If you look at our solar system...Take the distance of us from the sun, and the two nearest planets to us distances from the sun; ie mars and Venus, these two don't have any life, merely atm because of the distance from the sun due to too much heat or not enough of it.
Now take another solar system....They would need a sun equal to ours, plus planets around~ the same distance from the sun as ours...To even think about before having life forms equivalent to how ours started.
Granted you could have a smaller scaled sun with less heat, but the planets being closer and visa versa for a bigger sun but the solar system being larger etc...Then you mat have life as how we know it.
But then put into the facter that maybe how we have lived isn't the only way, and that we just haven't adapted to being able to live in such hostile enviroments such as Venus and Mars.
How likely is it to find a solar system like ours? With a planet like ours...Pretty much in the ONLY position it can be in, the perfect position, not too far, and not too close.
That's what I find interesting, how indeed likely it is to have another planet the same as ours. Therefore having life.